The clinically observable signs of tissue ageing that occur in elderly individuals—such as increased stiffness of the joints and vascular system,and increased fragility of the bones—arise from nanoscale changes in the two major structural proteins of the body, collagen, and elastin. In this study we evaluate (1) how degeneration of collagen acts systemically across organ systems and alters bone and skin material properties and (2) whether new markers of collagen properties assessed noninvasively in the skin can be used as diagnostics of bone material properties, which require an invasive biopsy to assess.

Key Findings: In a pilot study by our collaborators at the Hospital for Special Surgery, properties of the skin assessed by ultrasound, such as dermal layer thickness, were related to aspects of the bone micro structure, such as collagen crosslink maturity[1]. We are currently examining the relationships between (a) bone tissue properties assessed by spectroscopic and confocal imaging methods that require bone biopsies and (b) skin and bone properties assessed by inexpensive, noninvasive ultrasound and fluorescence methods, which could potentially serve as proxy measures for collagen content and bone material properties.

Representative multiphoton microscopy images of (A) a SHG image and (B) a fluorescence image in a cortical region of interest.

Future work: These findings will be used to assess fracture risk and potential surgical failures, and to develop new diagnostic tools with utility in aging-related disease prevention and treatment management.

Alexander Hughes, Hospital for Special Surgery